Evidence check: TCF7L2 in the context of Blutzucker

TCF7L2 is one of the strongest genetic loci associated with type 2 diabetes. Variants (e.g., rs7903146) increase risk for impaired glucose tolerance and fasting blood glucose, primarily through reduced insulin secretion. Effect size is moderate (odds ratio ~1.4 per risk allele), but penetrance is low: many carriers never develop diabetes. The association is confirmed in numerous GWAS and meta-analyses (human-strong). However, the predictive value of a single SNP for individual blood sugar is limited; lifestyle, diet, and other genetic factors dominate. MyBody-X is not a diagnostic tool – elevated genetic risk should prompt medical check-ups (e.g., HbA1c, OGTT), not self-treatment. Evidence comes from population studies, not clinical interventions. Caveat: effects vary by ancestry (best studied in European cohorts).